1. Technical Field
The disclosure relates to providing power over Ethernet, and particularly to a rectifier circuit and a powered device applied in power over Ethernet.
2. Description of Related Art
A power over Ethernet (POE) describes any of several standardized or ad-hoc systems which pass electrical power along with data through Ethernet cabling. This allows a single cable to provide both data connection and electrical power to devices. Unlike standards such as an universal serial bus (USB) which also power devices over the data cables, the POE allows long cable lengths.
In addition to standardizing existing practice for spare-pair and common-mode data pair power transmission, the POE standards provide for signaling between a power source equipment (PSE) and a powered device (PD). The signaling allows the presence of a conformant device to be detected by the PSE, and allows the device and source to negotiate the amount of power required or available. The PSE provides power through the Ethernet cable. The maximum allowed continuous output power per cable for the institute of electrical and electronic engineers (IEEE) 802.3af is 15.40 W, and the later specification, IEEE 802.3at, offers 25.50 W. The PD is powered by the PSE and consumes energy. Examples of the PD include wireless access points, internet protocol (IP) phones, and IP cameras. Therefore, it is necessary to provide a rectifier circuit with low power consumption for the POE.